Expander for random trim tubing

ABSTRACT

A tube expander operable with random length tubing having variable length projection beyond the face of header sheet into which the tube is to be expanded. Rollers in an expander cage are supported on a rotatable mandrel for insertion inward of the tube end. An open ended non-rotatable, tubular thrust collar is adapted to envelop the tube end and is secured about the cage at a predetermined location generally rearward of the rollers. Within the collar and biased toward the open end thereof is a slideable stop sleeve sized to abut the projecting end of the tube. On being advanced over the tube projection toward the header sheet for preliminary positioning, the collar engages the sheet face to register location of the rollers within the tube in alignment with the header sheet. Concomitantly with positioning of the collar, the abutting tube end acts to prevent sleeve movement as to effect relative displacement between sleeve and collar which can then be secured for operation of the expander.

United States Patent [1 1 Martin Sept. 23, 1975 EXPANDER FOR RANDOM TRIM TUBING [75] Inventor: Paul Warren Martin, Springfield,

Ohio

[73] Assignee: Dresser Industries, Inc., Dallas, Tex.

[22] Filed: July 17, 1974 [2]] Appl. No.: 489,226

Primary ExaminerLowell A. Larson Attorney, Agent, or Firm-Daniel Rubin 57 ABSTRACT A tube expander operable with random length tubing having variable length projection beyond the face of header sheet into which the tube is to be expanded. Rollers in an expander cage are supported on a rotatable mandrel for insertion inward of the tube end. An open ended non-rotatable, tubular thrust collar is adapted to envelop the tube end and is secured about the cage at a predetermined location generally rearward of the rollers. Within the collar and biased toward the open end thereof is a slideable stop sleeve sized to abut the projecting end of the tube. On being advanced over the tube projection toward the header sheet for preliminary positioning, the collar engages the sheet face to register location of the rollers within the tube in alignment with the header sheet. Concomitantly with positioning of the collar, the abutting tube end acts to prevent sleeve movement as to effect rela tive displacement between sleeve and collar which can then be secured for operation of the expander.

9 Claims, 7 Drawing Figures US Patent Sept. 23,1975 Sheet 2 of 2 3,906,771

FIG.3

FIG. 7'-

EXPANDER FOR RANDOM TRIM TUBING CROSS REFERENCE TO RELATED APPLICATIONS None.

BACKGROUND OFTHE INVENTION 1. The field of art to which the invention pertains generally comprises the art of metal deforming and more particularly to tube expanders of the roller and mandrel type for joining tubes into tube or header sheets.

2. Tube expanders are widely used by manufacturers of heat exchangers or the like for joining tube ends to header sheets and are available from a variety of commercial sources. In their usual construction, the roller and mandrel type tube expander is comprised of a tubular cage with three slots in its periphery containing rollers'lying at an oblique angle to the cage axis. A rotatable tapered mandrel extends axially through the cage in driving contact with the rollers to rotate the rollers while forcing them operably outward for expanding them against a tube sheet wall thereat. With the roller cage initially positioned internally of a tube in engagement against the tube wall, subsequent rotation of the mandrel induces a self-feeding inward movement thereof. Because of the self-feeding aspect, it is common to employ a stop collar of sorts which abuts against the tube end to prevent the tube from being drawn inward of the tool.

Equally important to the quality of the expander operation is the alignment registry of the expander rollers within the tube relative to the header face for each and every tube therein. Where all tubes project a uniform distance beyond the header face, the stop collar can be appropriately secured to obtain the necessary registry. However, a recent trend amoung manufacturers has been to purchase tubes of random length, such that tube projection beyond the header face varies from tube to tube. Under those circumstances the previous collar to tube end abutment cannot be relied on for obtaining the necessary registry within reasonable limits of accuracy. Despite recognition of the problem. a ready solution has not heretofore been known.

SUMMARY OF THE INVENTION The invention relates to tube expanders and more particularly to a novel construction thereof which insures accurately positioning the expander rollers within the tube without regard to variations among the tubes in their projection length beyond the header face. This is achieved in ,accordance herewith by means of a highly effective, yet relatively inexpensive construction employing a tubular thrust collar secured on the expander cage at a predetermined spacing rearward of the rollers. Contained within the thrust collar is a slideable stop sleeve biased forwardly toward the expander end and sized to abut against the tube end. In positioning the tool on a tube. the thrust collar can be advanced forwardly over the tube until the collar end face engages theheader face while the sleeve is essentially held by the tube end effecting relative displacement between the sleeve and collar. Once total displacement per tube is determined, the stop sleeve can be secured in position before initiating the expanding operation. Since tube projection will vary from tube to tube, displacement determination is repeated for each tube. In

thismanner, both alignment registry of the expander rollers relative to the tube sheet and prevention of tube draw are assured without regard to the degree of tube projection among the various tubes of the header sheet.

It is therefore an object of the invention to provide a novel tube expander capable of assuring both alignment registry of the expander rollers relative to the tube sheet and prevention of the tube draw without regard to projection length variation from tube to tube.

It is a further object of the invention to provide a novel tube' expander as in the previous object that is relatively simple and inexpensive to construct yet able to readily function with tubing cut to random length.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view ofa tube expander in accordance herewith shown at the onset of being positioned over a tube end projecting from a header sheet;

FIG. 2 is a view similar to FIG. 1 representing the condition of completed tool positioning on the tube;

FIG. 3 is a fragmentary enlargement of the encircled portion of FIG. 2 in a pre-locked relation;

FIG. 4 is a sectional view taken substantially along lines 4-4 of FIG. 3;

FIG. 5 is a fragmentary enlargement similar to FIG. 3 in a post-locked relation;

FIG. 6 is a sectional view taken substantially along lines 6-6 of FIG. 5; and v i FIG. 7 is asectional view similar to FlGS. l and 2 illustrating the post-expansion relation of the tool.

Referring now to the drawings, there is shown a tube expander in accordance herewith generally designated 10 and positioned internally of a tube 11 to be expanded for secured attachment to a tuhe sheet or header 12 having an end face 13. As specifically shown in FIG. 1, tube 11 projects beyond face 13 a variable distance X. x

Comprising the tube expander hereof is a tapered mandrel 14 adapted to be rotatably driven from its drive end 15. Positioned about the mandrel is a rotatablc cylindrical cage 16 containing a bearing ring I7 and three cylindrical forming rollers 18. The forming rollers have aligned heel end faces 19 and are circu mferentially displaced in the cage periphery obliquely skewed to its axis for support on the mandrel to be rotatably-driven thereby. I I

Surrounding the cage rearwardly of rollers 18 is an open ended thrust collar 22 supported on a thrust hearing 23 behind which is a thrust nut 24 positioned on cage threads 25 and secured thereto via a set screw 26. An annular retainer spring expanded inward of recess 31 maintains the components in their assembled relation whereby during the expanding operation collar 22 remains stationary relative to rotatable cage 16. Thrust collar 22 is ofgenerally tubular section that necks down to a nose 34 which terminates in a front .face 35 adapted'to abut tube sheet face 13. Centrally within nose 34 is defined a mouth or bore 36 of diameter sufficiently large to easily receive and envelop the projecting end of tube 11. Beyond nose 34 and originating from a shoulder 38 v bore 36 opens into an clongated enlarged central bore 37 continuously grooved or notched in'tandem on its internal periphery at 39.

Contained in central bore 37 is an annular stop sleeve 40 being slideably urged against shoulder 38 by means of a coil spring 41 compressed between the stop sleeve and thrust bearing 23. As most clearly shown in FIGS.

36. stop sleeve 40 is of generally tubular construction having a front end face 42 and a central throughbore 44 surrounding cage 16. Sufficient diametral clearance is afforded between the bore and cage to enable relative sleeve displacement in both an axial and radial direction as will be understood. Along its top periphery. the stop sleeve includes an axially extending flat 45 engageable by the nose end of a set screw 46. At its underside, the stop sleeve includes an enlarged diameter acutely angled arcuate segment 47 notched or grooved at its underside 48 in a circumferential direction for releaseably meshing or interfitting with bore notches 39.

In operation prior to positioning the tool on the tube end, collar 22 is axially secured on cage 16 via nut 24 and set screw 26 such that the plane of its end face 35 substantially aligns with heel end face 19 of rollers l8. This assures that when end face 35 engages header face 13. rollers 18 will be appropriately located within the width of header sheet 12. With set screw 46 loose. stop sleeve notches 48 are disengaged from bore notches 39 enabling the sleeve toessentially float forward in response to urging of spring 41 until the sleeve frontface 42 engaes bore shoulder 38. v

For operational setup, the tool is then placed onto a tube 11, projecting distance X beyond end face 13. until the tool components are essentially positioned in the manner of FIG. 1. This places sleeve end face 42 abutting the tube end with collar nose 35 displaced from header face 13 a distance Thereafter. the collar is slid forward over the tube end until its end face 35 engages header face 13 while movement of sleeve 40 is arrested by the abutting tube end (FIGS. 2-4). The relative displacement between collar and sleeve during this positioning step acts to increasingly compress spring 41. On attaining the displaced relation between collar and sleeve abutting the sheet face and tube end. respectively. set screw 46 is tightened downwardly as by wrench handle 52 until sleeve notches 48 mesh with and are secured in bore notches 39 in the manner shown in H05. 5 and 6. When the components are secured in the latter relationship. the tool can then be utilized for expanding the tube by motorized rotation of mandrel l4. Rotating the mandrel moves it leftwardly as viewed in the drawings to in turn force rollers l8 outwardly until expanding tube ll against the header sheet in the manner shown in FIG. 7. When tube expansion is completed. mandrel 14 is withdrawn enabling removal of the tool. Set screw 46 is then loos cned enabling stop sleeve notches 48 to disengage bore notches 39 whereby spring 41 can again float the sleeve forward against collar shoulder 38. When the latter is completed. the tool is in condition for repeat set up and rolling of the next tube.

By the above description there has been disclosed a novel tube expander particularly adapted for accommodating random length tubing to be expanded against a header sheet. By virtue of a displaceable sleeve internally of a thrust collar. it is possible to prevent tube draw while accurately and conveniently expanding each tube in proper registration alignment relative to the tube'header sheet without regard to the varying tube projection lengths beyond the header sheet existing among the various tubes. The apparatus is simple yet effective in resolving a long-standing problem for dealing with random cut tubing which has posed difficulties with tube expanders of the prior art.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof. it is intended that all matter contained in the drawings and specification shall be interpreted as illustrative and not in a limiting sense.

I claim: v

1. in a tube'expander for expanding an axially positioned tube to a header sheet beyond which the tube end is projecting and including a rotatable tubular cage for insertion in a tube end to be expanded, forming rollers contained in the outer periphery of said cage and a rotatabletapcred mandrel within said cage for driving said cage and rollers in an expanding relation to the tube end, the combination therewith of:

a. a non-rotatable tubular thrust collar operatively supported on said cage at a predetermined secured location displaced from said rollers, said collar having an inlet in which to receive the projecting end of a tube in which said cage is inserted and being movable thereover past the tube end toward the face of the header sheet; and

b. a stop sleeve slideably supported on said cage internally of said collar and abuttable against the end face of the received tube to be arrested by the tube end against movement together with said collar.

2. In a tube expander according to claim 1 in which the secured location of said collar relative to said cage rollers is presettably adjustable to substantially correlate with the expansion position setting of said rollers inward of the tube end relative to the face of the header sheet.

3. In a tube expander according to claim 1 including biasing means urging said stop sleeve toward the inlet of said collar.

4. ln a tube expander according to claim 1 including lock means to secure said stop sleeve to said collar at any displaced relation therebetwecn incurred by movement of said collar relative to said arrested sleeve.

5. in a tube expander according to claim 4 in which said lock means includes a releaseable interfit defined on the internal surface of said collar and the external surface of said sleeve.

6. in a tube expander according to claim 5 in which said releaseable interfit comprises a plurality of circumferentially extending arcuate peaks and notches formed in tandem on the surfaces of each of said collar and sleeve.

7. In a tube expander according to claim 6 in which the peaks and notches on said sleeve are contained on a arcuate segment extending radially outward from the adjacent periphery of said sleeve.

8. In a tube expander according to claim 7 in which the circumferential extent of said segment is defined by an acute angle and there is included screw means operable to move said sleeve radially into a secured engagement with the interfitting surfaces of said collar and sleeve.

9. In a tube expander according to claim 8 including spring means urging said stop sleeve toward the inlet of said collar. 

1. In a tube expander for expanding an axially positioned tube to a header sheet Beyond which the tube end is projecting and including a rotatable tubular cage for insertion in a tube end to be expanded, forming rollers contained in the outer periphery of said cage and a rotatable tapered mandrel within said cage for driving said cage and rollers in an expanding relation to the tube end, the combination therewith of: a. a non-rotatable tubular thrust collar operatively supported on said cage at a predetermined secured location displaced from said rollers, said collar having an inlet in which to receive the projecting end of a tube in which said cage is inserted and being movable thereover past the tube end toward the face of the header sheet; and b. a stop sleeve slideably supported on said cage internally of said collar and abuttable against the end face of the received tube to be arrested by the tube end against movement together with said collar.
 2. In a tube expander according to claim 1 in which the secured location of said collar relative to said cage rollers is presettably adjustable to substantially correlate with the expansion position setting of said rollers inward of the tube end relative to the face of the header sheet.
 3. In a tube expander according to claim 1 including biasing means urging said stop sleeve toward the inlet of said collar.
 4. In a tube expander according to claim 1 including lock means to secure said stop sleeve to said collar at any displaced relation therebetween incurred by movement of said collar relative to said arrested sleeve.
 5. In a tube expander according to claim 4 in which said lock means includes a releaseable interfit defined on the internal surface of said collar and the external surface of said sleeve.
 6. In a tube expander according to claim 5 in which said releaseable interfit comprises a plurality of circumferentially extending arcuate peaks and notches formed in tandem on the surfaces of each of said collar and sleeve.
 7. In a tube expander according to claim 6 in which the peaks and notches on said sleeve are contained on a arcuate segment extending radially outward from the adjacent periphery of said sleeve.
 8. In a tube expander according to claim 7 in which the circumferential extent of said segment is defined by an acute angle and there is included screw means operable to move said sleeve radially into a secured engagement with the interfitting surfaces of said collar and sleeve.
 9. In a tube expander according to claim 8 including spring means urging said stop sleeve toward the inlet of said collar. 